A crucial point in the development of today's and future vehicle systems is the increase of safety in road traffic. In addition to increasing the safety for vehicle occupants, this also involves increasing the safety for other road users, especially pedestrians or cyclists in road traffic. Therefore, the protection of pedestrians and cyclists in road traffic will find special consideration in future legislative proposals.
From the related art, there are sensors and evaluation devices which record the impact of objects on a vehicle and control the deployment of airbags to protect the vehicle occupants. Sensors of this type detect a deformation, or also a very great acceleration of the front or side sections of a vehicle. The disadvantage of such devices is that it is difficult to distinguish between persons and objects, thus, e.g., vehicles, obstacles or the like. Another disadvantage is that persons or objects are first detected and classified very late, so that there may not be sufficient time available for initiating protective measures.
Furthermore, so-called precrash detection systems for detecting road users and obstacles are known from the related art. For example, the German Patent DE 100 25 678 A1 discusses a method and a device for detecting road users and obstacles based on camera images for determining their distance from the observer and their classification. In so doing, potential opposing parties in an accident are recognized and identified in a two-step classification. The distance and the speed of the potential opposing party is estimated, and the road user is classified on this basis.
The German Patent DE 102 60 434 A1 discusses a method which measures the length of objects in front of a vehicle with the aid of radar sensors. On the basis of this linear measurement, the objects are classified and, based on that, for example, the mass of the objects is estimated.
Sensor systems based on cameras or radar sensors require complicated implementation and high costs associated with it.
So-called parking-aid assistants are also known, which determine the distance between a vehicle and an obstacle with the aid of an ultrasonic sensor system, and output warning signals to the driver of the vehicle if there is a drop below a specifiable threshold.